There are now available from various sources handheld computer devices having substantial memory capability as well as displays. These handheld devices very frequently prestore certain data such as date and time information, and are programmed to perform selected arithmetical functions. Some of these devices have the capability of transmitting and receiving data from larger computers and to permit that to be done, can be purchased with or are provided with such interface devices.
Those interface devices, for the purposes described above, and known to the applicants, are relatively bulky and may not be completely convenient to use for they are relatively bulky and/or require operating power from an external source.
Therefore, it is an object to provide novel interfaces useful for transferring data between computing devices of different sizes which interfaces are relatively compact and convenient to use.
A particular situation that must be dealt with is that usually one computer is connected to another device and the communication voltage levels of the two devices are different.
Therefore, it is a further object of this invention to provide a novel data interface that can receive data transmitted at a first voltage level from one device and supply at a second voltage level to a second device.
As will be appreciated, handheld computing or calculating devices are typically battery powered and to the extent that any device interfacing it with a larger computer draws on the batteries for power the operating life of the batteries is reduced.
Thus, it is another object of this invention to provide a novel data interface which utilizes the power supplied by a larger computer for its operation.